643. As regards the consonant

a. As regards the consonant of the reduplication, the general rules which have already been given above (590) are followed.

b. A long vowel is shortened in the reduplicating syllable: thus,

ददा dadā from √दा dā; बिभी bibhī from √भी bhī; जुहू juhū from √हू hū. The vowel ऋ ṛ never appears in the reduplication, but is replaced by इ i: thus, बिभृ bibhṛ from √भृ bhṛ; पिपृच्pipṛc from √पृच् pṛc.

c. For verbs in which a and ā also are irregularly represented in the reduplication by i, see below, 660. The root vṛt (V. B.) makes vavartti etc.; cakránt (RV.) is very doubtful.

d. The only root of this class with initial vowel is ṛ (or ar); it takes as reduplication i, which is held apart from the root by an interposed y: thus, iyar and iyṛ (the latter has not been found in actual use).